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Finding the Fourth Proportional to 288.40, 397.81 and 209.61

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Solution

The fourth proportional to 288.40, 397.81 and 209.61 is: 289.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.40 : 397.81 = 209.61 : x
  2. Step 2: Convert to fraction form
    288.40/397.81 = 209.61/x
  3. Step 3: Cross multiply
    288.40x = 397.81 × 209.61
  4. Step 4: Simplify right side
    288.40x = 83,382.97
  5. Step 5: Solve for x
    x = 83,382.97/288.40
  6. Step 6: Final answer
    x = 289.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.